Measurement device and dump truck travelling device

Abstract

To provide a measurement device and dump truck travelling device that can accurately perform load detection of dump trucks.SOLUTION: In a measurement device, which is provided in a dump truck 1 putting a load on a load-carrying platform 5 provided at an upper part of a vehicle body 2, and travelling, the measurement device has: an optical sensor 45 that is provided in a non-rotation part of the vehicle body 2 of the dump truck 1 not rotating upon travelling, and measures a distance L to a prescribed position of the rotating rotation part of the dump truck 1 upon travelling; a processor 210 that determines an estimation axle load W of the dump truck 1 on the basis of a measurement result of the optical sensor 45; a display unit 240 that displays the estimation axle load W determined by the processor 210; and a storage device 215 that stores correlation between a preliminarily measured actual measurement value of an axle load of the dump truck 1, and a measurement value of the distance. The processor 210 is configured to apply the correlation stored in the storage device 215 to a measurement value of the optical sensor 45 upon travelling, and determine a corresponding axle load W.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a measuring device provided on a dump truck that travels with a load carried thereon, and to a traveling device of the dump truck. [Background technology]

[0002] Patent Document 1 discloses a load sensor arrangement for mounting on an axle of a vehicle, which includes a load sensor for measuring the load applied to the axle, a sensor holder having a sensor holding portion and an attachment portion for mounting on the axle, wherein the load sensor is a magnetic sensor or an optical sensor, and the sensor holding portion holds the load sensor in a position on the axle for measuring direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] European Patent No. 3648996 Summary of the Invention [Problem to be solved by the invention]

[0004] However, for example, a dump truck may travel on a muddy road surface in wind and rain, and in such cases, the traveling device including the axles is exposed to various obstacles such as earth and sand, rocks, dust, rainwater, etc. Therefore, in a configuration in which a load sensor is provided on the axle as in Patent Document 1, the load sensor may be damaged by contact with the obstacles, and accurate load detection may not be possible.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a measuring device and a traveling device for a dump truck that can accurately detect the load of a dump truck. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a measuring device that is installed on a dump truck that travels with a load loaded on a loading platform installed on top of the vehicle body, the measuring device comprising: an optical sensor that is attached to a non-rotating part that does not rotate when traveling and that measures the distance to a predetermined position of a rotating part using emitted electromagnetic waves; a determination unit that determines an estimated axle weight of the dump truck based on the measurement results of the optical sensor; a display unit that displays the estimated axle weight determined by the determination unit; and a memory unit that stores a correlation between an actual measurement value of the axle weight of the dump truck that is measured in advance and an actual measurement value of the distance, wherein the determination unit applies the correlation stored in the memory unit to the measurement value of the optical sensor while traveling to determine the corresponding estimated axle weight. [Effects of the Invention]

[0007] According to the present invention, the load of a dump truck can be detected accurately. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side view showing a schematic structure of a dump truck according to an embodiment of the present invention. [Figure 2] FIG. 2 is a rear view of the dump truck shown in FIG. [Figure 3] FIG. 4 is a cross-sectional view showing the detailed structure of the left traveling device. [Figure 4] FIG. 4 is an enlarged view of part B in FIG. [Figure 5] 5 is a cross-sectional view taken along the arrows AA in FIGS. 3 and 4. FIG. [Figure 6] FIG. 2 is a partially cutaway perspective view showing a detailed structure in the vicinity of an optical measurement device, and an exploded perspective view of the optical measurement device. [Figure 7] 1 is an explanatory diagram showing deformation behavior near a rim and a wheel to explain the principle of axle load detection. FIG. [Figure 8] 10 is a graph showing the correlation between the weight of the load loaded on the bed and the deviation of the distance before and after loading for each type of dump truck. [Figure 9]FIG. 2 is a functional block diagram showing an electrical configuration of the dump truck. [Figure 10] 10A and 10B are a partially cutaway perspective view showing a detailed structure near an optical measurement device in a modified example in which the optical measurement device has a wiping function, and an exploded perspective view of the optical measurement device; [Figure 11] FIG. 2 is a side cross-sectional view showing a state in which the optical measurement device is assembled. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0010] <Dump truck outline> FIG. 1 shows a side view illustrating the schematic structure of a dump truck according to this embodiment, and FIG. 2 shows a rear view of the dump truck. In FIGS. 1 and 2, the dump truck 1 has a vehicle body 2 having a sturdy frame structure. Left and right front wheels 3 are rotatably provided on the front side of the vehicle body 2, and a left rear wheel 4L and a right rear wheel 4R (hereinafter collectively referred to as "rear wheels 4") are rotatably provided on the rear side of the vehicle body 2. The left front wheel 3L and the right front wheel 3R (hereinafter collectively referred to as "front wheels 3") constitute steered wheels that are steered by the driver of the dump truck 1. Front wheel suspensions 3A consisting of hydraulic shock absorbers or the like are provided between the vehicle body 2 and the left and right front wheels 3.

[0011] The left rear wheel 4L and the right rear wheel 4R constitute the drive wheels of the dump truck 1, and are respectively rotated and driven by the left traveling device 11L and the right traveling device 11R, which will be described later. As shown in FIG. 2, the rear wheels 4 include an inner tire 4A and an outer tire 4B in the axial direction, which are dual-wheel tires, and a wheel 15, which will be described later, on which they are mounted. A rim 14, which is a cylindrical part, is provided inside the inner tire 4A and the outer tire 4B. Rear wheel suspensions 4C, which are formed by hydraulic shock absorbers or the like, are provided between the vehicle body 2 and the left and right rear wheels 4.

[0012] A loading platform 5 is mounted on the vehicle body 2 so that it can be raised and lowered. The loading platform 5 is formed as a large container, for example, with a total length of about 10 meters, in order to carry a large amount of heavy cargo (cargo), such as crushed stone. The rear bottom of the loading platform 5 is connected to the rear end of the vehicle body 2 via a connecting pin 6 or the like so that it can be raised and lowered (tilted). A canopy portion 5A is integrally formed on the upper front side of the loading platform 5, covering the cab 7 (described below) from above.

[0013] The cab 7 is provided below the overhanging portion 5A provided on the loading platform 5 and at the front of the vehicle body 2, and forms a cab where the driver of the dump truck 1 gets in and out of. Inside the cab 7, a driver's seat, a start switch, an accelerator pedal, a brake pedal, a steering handle, a plurality of operating levers (none of which are shown), etc. are provided, and a display unit 240, which will be described later, is also provided.

[0014] The engine 8 is located below the cab 7 and is provided at the front of the vehicle body. The engine 8 is configured, for example, by a large diesel engine, and rotates and drives an on-board generator, a hydraulic pump serving as a hydraulic source (neither of which is shown), etc. Pressurized oil discharged from the hydraulic pump is supplied to a hoist cylinder 9 (described below), a steering cylinder for power steering (not shown), etc.

[0015] The hoist cylinders 9 are extendable in the vertical direction and are provided between the vehicle body 2 and the loading platform 5. The hoist cylinders 9 are located between the front wheels 3 and the rear wheels 4, and on both the left and right sides of the vehicle body 2. The hoist cylinders 9 extend and contract in the vertical direction as pressure oil is supplied and discharged from the hydraulic pump, and raise (tilt) the loading platform 5 around the connecting pin 6.

[0016] An axle housing 10 for the rear wheels 4 is provided on the lower rear side of the vehicle body 2. The axle housing 10 is formed as a cylindrical body extending left-right between the left rear wheel 4L and the right rear wheel 4R and constitutes part of the vehicle body 2. The axle housing 10 is attached to the rear side of the vehicle body 2 via a rear wheel suspension 4C. A spindle 12 (described below) is fixed to both left-right ends of the axle housing 10. A left-side traveling unit 11L and a right-side traveling unit 11R are provided on the left rear wheel 4L and the right rear wheel 4R, respectively. Note that the left-side traveling unit 11L and the right-side traveling unit 11R have the same configuration except that the left-side and right-side traveling units are reversed, so the following description will focus on the left-side traveling unit 11L provided on the left rear wheel 4L as an example. Hereinafter, the left-side traveling unit 11L and the right-side traveling unit 11R will be collectively referred to simply as the "travel unit 11."

[0017] <Traveling device> The detailed structure of the traveling device 11 (left traveling device 11L) is shown in Fig. 3. In Fig. 3, the traveling device 11 includes a spindle 12, a wheel 15, wheel bearings 17 and 18, an electric motor 21, a shaft 22, and a planetary gear reduction device 25 (speed reducer). The traveling device 11 reduces the rotation of the electric motor 21 by the planetary gear reduction device 25, and drives the rear wheels 4, which are the drive wheels of the dump truck 1, with a large rotational torque.

[0018] <Spindle> The spindle 12 is formed in a stepped cylindrical shape extending in the axial direction within the wheel 15. The spindle 12 has a large-diameter cylindrical portion 12A located on one side in the axial direction, an intermediate cylindrical portion 12B located in the middle of the axial direction, a small-diameter cylindrical portion 12C located on the other side in the axial direction, and a flange portion 12D located at the boundary between the large-diameter cylindrical portion 12A and the intermediate cylindrical portion 12B.

[0019] The large-diameter cylindrical portion 12A gradually narrows in diameter toward the intermediate cylindrical portion 12B, like a funnel or mortar shape. One axial end of the large-diameter cylindrical portion 12A is fixed to the edge of the axle housing 10 (see FIG. 1) using multiple bolts. The electric motor 21 is attached to one axial end of the large-diameter cylindrical portion 12A.

[0020] The small diameter cylindrical portion 12C is formed in a cylindrical shape with a smaller diameter than the intermediate cylindrical portion 12B and is disposed on the inner peripheral surface side of the wheel 15. The small diameter cylindrical portion 12C rotatably supports the wheel 15 via the wheel bearings 17 and 18. The other axial end (tip) of the small diameter cylindrical portion 12C is an open end, and a hole spline 12G is formed by splining on the inner peripheral surface on the other side in the axial direction of the small diameter cylindrical portion 12C. The hole spline 12G of the small diameter cylindrical portion 12C is coupled to a shaft spline 39B that is splined on the outer peripheral surface of a second-stage carrier 39, which will be described later. A brake device 41, which will be described later, is fixed to the flange portion 12D.

[0021] <Wheels> The wheel 15 is provided on the other axial side of the spindle 12, on the outer periphery of the spindle 12. An inner tire 4A and an outer tire 4B of the rear wheel 4 are mounted on the wheel 15. Wheel bearings 17 and 18 are provided between the small diameter cylindrical portion 12C of the spindle 12 and the wheel 15, and support the wheel 15 rotatably on the outer periphery of the spindle 12.

[0022] <Electric motor shaft> The electric motor 21 is provided as a rotation source on one side of the spindle 12 in the axial direction. The electric motor 21 rotates a rotor (not shown) in a forward or reverse direction by electric power supplied from a generator (not shown) mounted on the vehicle body 2, and the rotation of the rotor is output by an output shaft 21B having a substantially horizontal axis k (rotation axis). The base end of the output shaft 21B is integrally connected to the rotor of the electric motor 21, and the tip of the output shaft 21B protrudes outside from the casing of the electric motor 21. The shaft 22 is coaxially connected to the tip of the output shaft 21B.

[0023] The shaft 22 is formed of a single rod-shaped body that is inserted axially into the inner peripheral surface of the small-diameter cylindrical portion 12C of the spindle 12. One axial side (base end side) of the shaft 22 is coupled (spline-coupled) to the output shaft 21B of the electric motor 21. The other axial side (tip side) of the shaft 22 protrudes from the other axial end (open end of the small-diameter cylindrical portion 12C) of the spindle 12 toward the planetary gear reduction device 25, and a sun gear 27, which will be described later, is attached to the tip of the shaft 22. As a result, the shaft 22 inputs the rotation of the output shaft 21B of the electric motor 21 to the planetary gear reduction device 25.

[0024] <Planetary gear reduction device> Planetary gear reduction device 25 is provided on the other axial side of spindle 12, between wheel 15 and shaft 22, and is composed of a first-stage planetary gear reduction mechanism 26 and a second-stage planetary gear reduction mechanism 34. Planetary gear reduction device 25 reduces the rotational driving force of electric motor 21 (output shaft 21B) transmitted via shaft 22 in two stages and transmits it to wheel 15. As a result, wheel 15 is rotated by both inner tire 4A and outer tire 4B of rear wheel 4 with a large rotational force (torque).

[0025] <First stage planetary gear reduction mechanism> The first-stage planetary gear reduction mechanism 26 is composed of a sun gear 27 splined to the tip of the shaft 22, multiple planetary gears 29 meshing with the sun gear 27 and a ring-shaped internal gear 28, and a carrier 31 that rotatably supports the multiple planetary gears 29.

[0026] The outer circumferential side of the carrier 31 is detachably fixed to the other axial end face of the outer drum 23, which is integrated with the wheel 15. Internal teeth are formed around the entire inner circumferential surface of the internal gear 28, and a plurality of planetary gears 29 are constantly meshed with these internal teeth. The rotation of the internal gear 28 is transmitted to a second-stage planetary gear reduction mechanism 34 via a coupling 33.

[0027] When the sun gear 27 rotates integrally with the shaft 22 due to the electric motor 21, the first-stage planetary gear reduction mechanism 26 converts the rotation of the sun gear 27 into rotational motion and revolutional motion of the planetary gears 29. The rotational driving force due to the rotation (rotation) of the planetary gears 29 is transmitted to the internal gear 28, causing the internal gear 28 to rotate. The rotational driving force of the internal gear 28 is transmitted to the second-stage planetary gear reduction mechanism 34 via a coupling 33. Meanwhile, the carrier 31 rotates in accordance with the revolution of the planetary gears 29, and the rotational driving force of the carrier 31 is transmitted to the outer drum 23. In this case, the outer drum 23 is integrated with the wheel 15 and the internal gear 36. Therefore, the revolution of the planetary gears 29 is suppressed to rotate in synchronization with the internal gear 36.

[0028] The coupling 33 is provided between the first-stage planetary gear reduction mechanism 26 and the second-stage planetary gear reduction mechanism 34, and rotates integrally with the first-stage internal gear 28. The outer periphery of the coupling 33 is spline-connected to the first-stage internal gear 28. The inner periphery of the coupling 33 is spline-connected to the second-stage sun gear 35, which will be described later. The coupling 33 transmits the rotational driving force of the first-stage internal gear 28 to the second-stage sun gear 35, causing the sun gear 35 to rotate integrally with the first-stage internal gear 28.

[0029] <Second-stage planetary gear reduction mechanism> The second-stage planetary gear reduction mechanism 34 is composed of a cylindrical sun gear 35 arranged on the outer periphery of the shaft 22, multiple planetary gears 37 meshing with the sun gear 35 and the ring-shaped internal gear 36, and a cylindrical second-stage carrier 39 that rotatably supports the multiple planetary gears 37.

[0030] The second stage internal gear 36 is integrally fixed between the wheel 15 and the outer drum 23 using a long bolt. Internal teeth are formed on the inner peripheral surface of the internal gear 36 over the entire circumference, and a plurality of planetary gears 37 mesh with these internal teeth.

[0031] A cylindrical protrusion 39A protruding toward the spindle 12 is integrally formed at the center of the second-stage carrier 39. A shaft spline 39B formed on the outer peripheral surface of one axial side (spindle 12 side) of the cylindrical protrusion 39A is spline-engaged with a hole spline 12G formed in the small-diameter cylindrical portion 12C of the spindle 12. Therefore, the second-stage carrier 39 is unable to rotate with respect to the spindle 12.

[0032] In the second-stage planetary gear reduction mechanism 34, the cylindrical protrusion 39A of the second-stage carrier 39 is spline-coupled to the small-diameter cylindrical portion 12C of the spindle 12, thereby restricting the revolution of the planetary gear 37 (the rotation of the second-stage carrier 39). When the sun gear 35 rotates integrally with the coupling 33, the second-stage planetary gear reduction mechanism 34 converts this rotation of the sun gear 35 into the rotation of the planetary gears 37. The rotation of the planetary gears 37 is transmitted to the internal gear 36, which rotates at a reduced speed. As a result, a high-output rotational torque that has been reduced in two stages by the first-stage planetary gear reduction mechanism 26 and the second-stage planetary gear reduction mechanism 34 is transmitted to the wheel 15 to which the internal gear 36 is fixed, thereby driving the rear wheel 4 to rotate.

[0033] <Brake hubs and brake devices> A brake hub 40 is attached to the other end face of the wheel 15, on which the outer drum 23 is not attached. The brake hub 40 is formed as a cylindrical body extending in the axial direction between the wheel 15 and a braking device 41, which will be described later. The other axial side (the wheel 15 side) of the brake hub 40 is fixed to the end face of the wheel 15.

[0034] An enlarged view of part B in Fig. 3 is shown in Fig. 4. In Fig. 4 and Fig. 3, the brake device 41 is provided between the spindle 12 and the wheel 15 via a brake hub 40. In this example, the brake device 41 is configured as a wet multi-plate hydraulic brake, and applies a braking force to the wheel 15. The brake device 41 has a brake housing 41A, and the brake housing 41A is attached to the flange portion 12D of the spindle 12.

[0035] <Dump truck driving motion> The basic operation of the dump truck 1 configured as described above will now be described. For example, when the driver in the cab 7 of the dump truck 1 manually starts the engine 8, the hydraulic pump serving as the hydraulic source is driven to rotate, and the generator generates electricity. When the dump truck 1 is traveling, power is supplied from the generator to the electric motor 21, which activates the electric motor 21 to rotate the output shaft 21B, which in turn rotates the shaft 22 connected to this output shaft 21B.

[0036] The rotational drive force of the shaft 22 is transmitted from the sun gear 27 of the first-stage planetary gear reduction mechanism 26 to the plurality of planetary gears 29. The rotational drive force of the plurality of planetary gears 29 is transmitted to the sun gear 35 of the second-stage planetary gear reduction mechanism 34 via the internal gear 28 and the coupling 33. The rotational drive force of the sun gear 35 is transmitted to the plurality of planetary gears 37. At this time, the shaft spline 39B of the second-stage carrier 39 that supports the planetary gears 37 is spline-coupled with the hole spline 12G of the spindle 12, so that the rotation of the second-stage carrier 39 (the revolution of the planetary gears 37) is restricted.

[0037] As a result, the planetary gear 37 only rotates around the sun gear 35, and a rotational driving force slowed down by the rotation of the planetary gear 37 is transmitted to the internal gear 36 fixed to the wheel 15. Therefore, the wheel 15 rotates with a large rotational torque that is reduced in two stages by the first-stage planetary gear reduction mechanism 26 and the second-stage planetary gear reduction mechanism 34. As a result, the left and right rear wheels 4, which serve as drive wheels, rotate integrally with the wheel 15, allowing the dump truck 1 to travel. In this way, the dump truck 1 travels between a loading area where cargo such as crushed stone excavated from a mine is loaded onto the bed 5, and an unloading area where the cargo loaded on the bed 5 is unloaded. As described above, the output shaft 21B, shaft 22, various parts of the planetary gear reduction device 25, wheel 15, rear wheel 4, etc., which rotate due to the rotational driving force of the electric motor 21, constitute a rotating part provided on the vehicle body 2 that rotates when the vehicle is running.

[0038] <Plate> 4 and 3, a brake housing 41A is fastened to the flange portion 12D of the spindle 12 with a bolt 43. A substantially annular plate 44 (dustproof member) is inserted between the bolt 43 and the brake housing 41A and fastened together. That is, in this embodiment, the non-rotating portion of the dump truck 1 includes at least the spindle 12, the plate 44, and the brake device 41. In detail, as shown in FIG. 5, which is a cross-sectional view taken along the line AA in FIGS. 3 and 4, the plate 44 is configured to be separable at a predetermined portion of the substantially annular shape into two semicircular separate pieces, an upper plate portion 44U and a lower plate portion 44L. That is, as shown in FIGS. 3, 4, and 5, the upper plate portion 44U and the lower plate portion 44L are fastened together with the bolt 43 that fastens the flange portion 12D and the brake housing 41A, thereby covering the entire circumference of the flange portion 12D. However, the plate 44 is not limited to being composed of two parts, and may be composed of three or more parts as long as it has a structure that covers the entire circumference of the flange portion 12D of the spindle. Hereinafter, the upper plate portion 44U and the lower plate portion 44L will be collectively referred to simply as the "plate 44" as appropriate. The plate 44 is formed with a plurality of flange portions 44A that protrude toward the inner diameter side, and each flange portion 44A is provided with a plurality of holes 44a (see FIG. 4) through which the bolts 43 can be passed. In addition, the outer peripheral end of the plate 44 extends to the vicinity of the inner diameters of the inner tire 4A and the outer tire 4B, specifically, to the vicinity of the inner diameter of the rim 14 (see FIG. 4).

[0039] <Optical measurement device> An optical measuring device 45 is fixed to the plate 44 having the above structure by welding. The optical measuring device 45 measures the distance L in the approximately horizontal direction (in other words, the direction along the axis k) to the flange end surface 15A of the wheel 15, which is a part of the rotating part and is a predetermined position (deformed portion) to be measured, by a known optical method. Note that the optical measuring device 45 may be fixed to the plate 44 not only by welding, but also by screw connection using bolts or the like.

[0040] FIG. 6(a) shows a partially cutaway perspective view illustrating the detailed structure of the optical measurement device 45 and its surroundings, and FIG. 6(b) shows an exploded perspective view of the optical measurement device 45. In FIGS. 6(a) and 6(b), the optical measurement device 45 is composed of four components: an angle 45A, a sensor body 45B (optical sensor) that emits a predetermined electromagnetic wave, e.g., light, a cover 45C, and a bolt 45D. The substantially U-shaped angle 45A, which serves as the base of the optical measurement device 45, is fixed to the plate 44 by welding, and the sensor body 45B is inserted into the substantially U-shaped space between the angle 45A and the angle 45A. A cover 45C (dustproof wall) is attached to cover at least the measurement side of the optical measurement device 45 (in this example, to cover the inserted sensor body 45B and angle 45A). Bolts 45D are screwed into the top of cover 45C, and cover 45C is joined to angle 45A to fix sensor main body 45B inside. Cover 45C is provided with a light-transmitting opening 45Ca that allows light to exit from sensor main body 45B and enter sensor main body 45B.

[0041] <Load detection principle> The principle of axle load detection using the optical measuring device 45 according to this embodiment will be described below. For example, as shown in FIG. 7, the distance L to the flange end surface 15A of the wheel 15 detected by the optical measuring device 45 (for convenience of illustration, the optical measuring device 45 in the modified example (1) described below is shown) is L = Lo when there is no load on the loading platform 5 (the state shown by the solid line in the figure). In contrast, when a heavy load such as the above-mentioned crushed stone is loaded on the loading platform 5, the rim 14 and the wheel 15 are deformed by the load (the state shown by the dashed line in the figure). As a result, the position of the flange end surface 15A detected by the optical measuring device 45 changes, and the distance L changes from Lo to L = L1. In other words, the loading of the load on the loading platform 5 causes a deviation of the distance L ΔL = L1 - L0 (hereinafter simply referred to as the distance deviation ΔL). The flange end surface 15A corresponds to the predetermined position (deformed portion) of the rotating part to be measured.

[0042] <Correlation between distance deviation △L and axle load W> The inventors of the present application conducted an experiment for a dump truck 1 in a non-traveling state to determine the relationship between the distance deviation ΔL and the load due to the weight of the load on the loading platform 5 (more specifically, the axle load W applied to either the left or right traveling gear 11; hereinafter simply referred to as "axle load W"). That is, the dump truck 1 in a non-traveling state with an appropriate amount of cargo loaded on the bed 5 was placed on a known weight measuring device, the weight at that time (weight of the dump truck 1 itself + weight of the cargo) was measured, and the axle load W was calculated based on the value obtained by subtracting the weight of the dump truck. In addition, the aforementioned distance L = L1 occurring at that time was measured with the optical measuring device 45, and the distance deviation ΔL = L1 - L0 from the distance L = L0 before the cargo was loaded was calculated. The above measurements and calculations were carried out in multiple patterns while varying the amount of cargo on the loading platform 5. As a result, it was found that there is a specific correlation between the weight (axle load W) of the cargo loaded on the loading platform 5 and the deviation ΔL of the distance L before and after loading for each type of dump truck 1.

[0043] 8(a) and 8(b) show examples of correlations discovered by the inventors of the present application using the above method.

[0044] FIG. 8(a) is a diagram showing the measurement results when experiments were conducted on a dump truck 1 of vehicle type A with various amounts of loaded loads as described above, plotted with ●, with the distance deviation ΔL on the horizontal axis and the axle load W on the vertical axis. As shown in the figure, in this example, there is a relationship between the distance deviation ΔL and the axle load W. W=K1×△L+W01 (Formula 1) It was found that a nearly linear correlation was observed, as expressed by the following equation.

[0045] FIG. 8(b) is a diagram showing the measurement results plotted with ● when an experiment was conducted on a dump truck 1 of vehicle type B with various load amounts, as described above. As shown in the figure, in this example, there is a relationship between the distance deviation ΔL and the axle load W, W=K2×△L+W02 (Formula 2) It was found that a nearly linear correlation was observed, as expressed by the following equation.

[0046] Although not shown in the drawings, the inventors of the present application have also conducted similar measurement experiments on dump trucks 1 of other vehicle types in addition to those shown in FIGS. 8(a) and 8(b) above, and obtained similar results to those described above. As a result of the above, for dump truck 1, the relationship between distance deviation △L and axle load W is as follows: W=K×△L+W0 ··· (Formula 3) K: A specific correction coefficient determined for each vehicle model W0: A unique constant determined for each vehicle model It has been found that the general formula represented by the following holds true.

[0047] As a result, it was found that if the above experiment is performed in advance for all vehicle types of dump truck 1, correlations such as those in Equation 1 and Equation 2 are calculated and stored in an appropriate location, and the distance deviation ΔL based on the detection results of the optical measuring device 45 during actual driving is applied, the axle load W can be determined (estimated) in real time.

[0048] <Dump truck electrical configuration> The electrical configuration of the dump truck 1 of this embodiment, which is provided to realize the above-described method, is shown in Fig. 9. In Fig. 9, the dump truck 1 has a processor 210, a storage device 215 (storage unit), a display unit 240, an operation unit 250, the optical measuring device 45, a communication interface 270, and the electric motor 21. The processor 210, the storage device 215, the display unit 240, the operation unit 250, the optical measuring device 45, the communication interface 270, and the electric motor 21 are connected via a bus 205 so as to be able to transmit and receive data to and from each other.

[0049] The storage device 215 includes a volatile storage device 220 and a non-volatile storage device 230. The volatile storage device 220 is, for example, a DRAM, and includes a data storage area 221 that temporarily stores various data. The non-volatile storage device 230 is, for example, a flash memory, and includes a program storage area 232 and a correlation storage area 233.

[0050] Various programs are stored as firmware, for example, in the program storage area 232. These programs include an axle load determination program for executing the method of estimating the axle load W from the distance deviation ΔL described above with reference to Figures 8(a) and 8(b).

[0051] The correlation storage area 233 stores the above-mentioned formula 1, the correction coefficient K corresponding to each vehicle model, and the constant W0. Alternatively, the above-mentioned formula 2, formula 3, ..., etc. corresponding to each vehicle model may be stored. Alternatively, the values ​​of axle load W for each predetermined range of the distance deviation △ according to the above formulas 2, 3, etc. corresponding to each vehicle type may be stored, for example, in a table format, etc. In this case, for a certain vehicle type, values ​​for each range are stored in appropriate increments, such as axle load W = 100 [tons] when the distance deviation △ is 0 [mm] or more and less than 1 [mm], axle load W = 130 [tons] when the distance deviation △ is 1 [mm] or more and less than 2 [mm], and axle load W = 160 [tons] when the distance deviation △ is 2 [mm] or more and less than 3 [mm].

[0052] The processor 210 is a device that performs data processing, such as a CPU. The processor 210 executes various programs, including the axle load determination program, stored in the program storage area 232. The function of the processor 210 that executes the axle load determination program to estimate the axle load W based on the measurement results of the optical measuring device 45 (in other words, the function of determining the estimated axle load W) corresponds to a determination unit.

[0053] The display unit 240 is provided in the cab 7 and is, for example, a liquid crystal display capable of displaying various information. In particular, in this embodiment, the axle load W determined by the processor 210 as described above is displayed on the display unit 240. The processor 210, the storage device 215, the display unit 240, and the optical measurement device 45 constitute a measurement device.

[0054] The operation unit 250 is a device that accepts operations by a user. The user can input various instructions to the dump truck 1 by operating the operation unit 250. For example, the user can input the vehicle type of the dump truck 1 described above to the processor 210 via the operation unit 250. Alternatively, the user may be able to input the correction coefficient K and constant W0 specific to each vehicle type described above as appropriate via the operation unit 250. Furthermore, by inputting user identification information (such as a user ID) into the operation unit 250, the processor 210 may automatically select the vehicle type, or the correction coefficient K and constant W0.

[0055] The communication interface 270 is a wired or wireless network interface for communicating data with other devices. For example, before the dump truck 1 is put into operation, a correlation (such as a general formula like the above-mentioned Formula 1, or a formula specific to each vehicle model like Formula 2 or Formula 3) derived based on the measurement results of the weight measuring device as described above is input to the storage device 215 via the communication interface 270 and stored in the correlation storage area 233 of the nonvolatile storage device 230.

[0056] <Real-time axle load determination while driving> In the dump truck 1 having the above configuration, the above-described axle load determination method is executed in real time while the dump truck 1 is traveling as follows.

[0057] In other words, when the dump truck 1 is traveling, the rear wheel 4, rim 14, and wheel 15 rotate around the outer periphery of the traveling device 11, and the impact load applied during traveling is transmitted to the wheel 15 through the rear wheel 4 and rim 14, and the position of the flange end face 15A of the wheel is displaced by the transmitted load. At this time, the optical measuring device 45 is provided above the brake device 41, which is a non-rotating part, so the above-mentioned displacement does not occur, and the optical measuring device 45 constantly measures the distance to the flange end surface 15A of the wheel 15 (in this case, the distance L1 because a load is being carried) while the dump truck 1 is traveling. The measured distance L1 is input from the optical measuring device 45 to the processor 210. The processor 210 determines the axle load W by applying the correlation stored in the correlation memory area 233 to the deviation Δ (= L1 - L0) between the distance L1 measured in real time during travel and the distance L0 detected in an unladen state before the travel.

[0058] <Effects of the embodiment> As described above, in this embodiment, when the dump truck 1 travels with a load loaded on the bed 5, deformation due to the weight of the load is detected. That is, the optical measuring device 45 provided in the non-rotating part of the body 2 of the dump truck 1 measures the distance L to the deformed part where the deformation has occurred in the rotating part of the dump truck 1 (in the above example, the flange end surface 15A of the wheel 15, which corresponds to the predetermined position to be measured). The measurement result is input to the processor 210, and the processor 210 converts the measured distance L into an axle load W of the dump truck 1 to determine an estimated axle load W, and the determined estimated axle load W is displayed on the display unit 240.

[0059] As described above, in this embodiment, the axle load W of the dump truck 1 is detected based on the distance L to a predetermined position (deformed portion) to be optically measured. Therefore, unlike conventional methods in which the load is directly detected using a sensor attached to the axle, the optical measuring device 45 can be placed in a position (a dust-proof position) that is not exposed to various obstacles such as earth and sand, rocks, dust, and rainwater. This prevents damage to the sensor due to the above obstacles, allowing for accurate axle load detection. Furthermore, optical measurement of the rotating part can be performed non-contact by the optical measuring device 45 in the non-rotating part, which is separated from the rotating part, so there is no need to worry about interference with the rotational movement of the rotating part.

[0060] The dustproof effect on the optical measuring device 45 will be described in detail below. That is, the rim 14 and rear wheels 4 are attached to the outer periphery of the traveling device 11, and they rotate together with the wheels 15 while traveling. Since the dump truck 1 travels on roads that are not paved with asphalt or the like, such as in mines, dust and other particles may be generated while traveling. Therefore, there is a risk that the dust adhering to the rear wheels 4 and the dust that is kicked up while traveling may enter through the gap M (see Figures 3 and 7) between the inner tire 4A, the outer tire 4B, and the large-diameter cylindrical portion 12A of the spindle, and fly toward the brake device 41 of the traveling device 11 or the wheels 15.

[0061] In this embodiment, taking the above into consideration, the optical measuring device 45 is provided on the brake device 41 side of the plate 44 attached to the flange portion 12D of the spindle 12, which is the opposite side from the intrusion side. In addition, the outer peripheral end of the plate 44 extends to the vicinity of the inner diameter of the rim 14. As a result, the plate 44 blocks the soil and dust that invade through the gap M, preventing them from flying toward the optical measuring device 45. As a result of this dustproof effect, damage to the optical measuring device 45 can be prevented, and the axle load W can be accurately detected.

[0062] Furthermore, in this embodiment, as described above, the optical measuring device 45 is provided on the outer periphery of the traveling device 11. Therefore, not only can the optical measuring device 45 be installed when assembling the traveling device 11 when manufacturing a new dump truck 1, but the optical measuring device 45 can also be attached to the structure of an existing dump truck 1 as a retrofit. In other words, there is an advantage that it is not necessary to disassemble the traveling device 11 of an existing dump truck 1. This effect will be described in detail below.

[0063] That is, the optical measuring device 45 is attached to the vehicle body 2 of the existing dump truck 1, for example, as follows. First, a hydraulic cylinder is inserted from below into the axle housing 10 (see Figure 1) of a parked dump truck 1, the vehicle body 2 is lifted, and the rear wheels 4 are lifted off the ground. Nuts 50 (see Figure 3) fastening the rear wheels 4 and rims 14 to the traveling devices 11 are removed. Then, the rear wheels 4 and rims 14 inserted into the outer periphery of the wheels 15 are removed. By removing the rims 14, the outer periphery of the braking devices 41 is exposed.

[0064] Thereafter, the bolts 43 originally attached to the flange portion 12D are removed, and with the plate 44 attached to the flange portion 12D, the bolts 43 at the removed locations are fastened again, thereby fixing the plate 44 to the spindle 12. The optical measuring device 45 is joined to the fixed plate 44 by welding or bolting.

[0065] Thereafter, the rim 14 and rear wheel 4 are assembled in the reverse order of the removal procedure described above, and fastened with the nut 50. After fastening, the hydraulic cylinder provided in the axle housing 10 is removed, and the rear wheel 4 is allowed to land on the ground. As described above, in this embodiment, the optical measuring device 45 can be installed in an existing dump truck 1 without disassembling the traveling device 11.

[0066] Furthermore, in this embodiment, the axle load W of the dump truck 1 and the corresponding distance L measured by the optical measuring device 45 are measured in advance, and the correlation between these two measured values ​​is stored in the correlation storage area 233 of the non-volatile storage device 230 of the storage device 215. Then, when the optical measuring device 45 measures the distance (distance L1 in the above example) while the dump truck 1 is traveling, the processor 210 applies the above correlation based on the measured distance L1 to derive the corresponding axle load W of the dump truck 1, and this value becomes the estimated axle load W. According to this embodiment, the corresponding estimated axle load W can be smoothly determined based on the measurement value of the optical measuring device 45 while the vehicle is traveling.

[0067] Furthermore, as described above, there are cases where deformation characteristics due to the weight of the loaded object vary depending on the vehicle type of the dump truck 1. As described above, in this embodiment, the actual measured value of the distance L measured in advance by the optical measuring device 45 and the axle load W of the dump truck 1 are correlated and stored, but when a plurality of vehicle types are used in the dump truck 1, it is necessary to take into consideration the differences in deformation characteristics depending on the vehicle type as described above. Therefore, in this embodiment, when the processor 210 determines the axle load W, a correction coefficient K set for each vehicle type of the dump truck 1 is used in the calculation (see the above formulas 1, 2, and 3). As a result, no matter what vehicle type of dump truck 1 is used, accurate detection of the axle load W can be performed.

[0068] Furthermore, particularly in this embodiment, in the optical measuring device 45, the cover 45C has a light transmitting opening 45Ca that allows light to be emitted from the sensor main body 45B and light to be incident on the sensor main body 45B, and covers at least the measurement execution side of the optical measuring device 45. By providing this cover 45C, it is possible to prevent dust and the like from entering the measurement space of the optical measuring device 45 and reducing the measurement accuracy.

[0069] Furthermore, in this embodiment, measurement is performed in a substantially horizontal direction from the optical measurement device 45 disposed on the non-rotating part to a predetermined position on the rotating part (the deformed part; in the above example, the flange end surface 15A of the wheel 15). This minimizes the influence of dust particles and the like that may be present in the measurement execution space of the optical measurement device 45, preventing a decrease in measurement accuracy.

[0070] Furthermore, particularly in this embodiment, the substantially annular plate 44 is configured to be separable in the circumferential direction. As a result, as already described, when, for example, retrofitting the optical measuring device 45 to an existing dump truck 1, it is sufficient to remove only the separate piece to which the optical measuring device 45 is to be attached from the dump truck 1 among the multiple separate pieces (the upper plate portion 44U or the lower plate portion 44L in the above example), attach the optical measuring device 45 to the removed separate piece, and then return it to its original position. In other words, since there is no need to remove the entire substantially annular plate 44, the above retrofitting work can be easily performed.

[0071] In this embodiment, the optical measuring device 45 measures the distance L to the end face of the wheel 15. By having the optical measuring device 45 measure the wheel 15 equipped with the inner tire 4A and the outer tire 4B, which are prone to relatively large deformation due to the loading of cargo onto the loading platform 5, highly accurate load detection can be performed reliably.

[0072] <Modification> The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and technical concept of the present invention. Such modifications will be described below in order. The same reference numerals will be used to designate parts equivalent to those in the above-described embodiment, and descriptions will be omitted or simplified as appropriate.

[0073] (1) When the optical measuring device has a wiping function This modified example will be described with reference to Figures 10(a), 10(b), and 11. Figure 10(a) is a partially cutaway perspective view showing the detailed structure of the optical measuring device 45 and its vicinity in this modified example, and Figure 10(b) is an exploded perspective view of the optical measuring device 45. Also, Figure 11 is a side cross-sectional view showing the optical measuring device 45 in an assembled state.

[0074] 10(a), 10(b), and 11, the optical measuring device 45 of this modified example has a cleaning function (wiping function) for protecting itself. That is, a bracket 46A, which is a housing of the optical measuring device 45, is attached by welding to the plate 44 attached to the flange portion 12D of the spindle 12. Note that the method of attaching the bracket 46A to the plate 44 is not limited to welding, and may be, for example, a screw connection using bolts or the like.

[0075] A top plate 46B (dustproof wall) is provided in front of the optical measurement device 45. A light-transmitting opening 46C (light-transmitting opening) for a sensor is fitted into a hole provided in the top plate 46B, and a sensor main body 46D (optical sensor) is mounted on top of that. Furthermore, the sensor main body 46D is held down and fixed from above by a bracket 46E, and the top plate 46B, light-transmitting opening 46C, sensor main body 46D, and bracket 46E are fixed together by a fixing device 46F such as a screw.

[0076] A bushing 46I is inserted into a hole 46Ba drilled in the center of the top plate 46B, and a rotating tool 46G is attached to the tip of the bushing 46I. Meanwhile, an output shaft 46Ja of a motor 46J is inserted into the base end of the bushing 46I, and the motor 46J is fixed to the top plate 46B with a bolt 46K. At this time, a rubber material (or an adsorbent material) 46H is attached to the back surface of the rotating tool 46G, and when the rotating tool 46G rotates, the rubber material 46H slides over the light-transmitting opening 46C, wiping it. The motor 46J, rotating tool 46G, and rubber material 46H constitute a wiping mechanism.

[0077] During assembly, the top plate 46B equipped with the sensor main body 46D and the motor 46J is inserted into the bracket 46A from the motor 46J side, and after the sensor main body 46D, motor 46J, and various associated parts are placed inside the bracket 46A, the top plate 46B and the bracket 46A are fixed together by welding. However, the joining of the top plate 46B and the bracket 46A is not limited to welding, and may be, for example, a screw connection using bolts.

[0078] In this modification, while the dump truck 1 is traveling, a motor 46J mounted inside the optical measuring device 45 is started, causing the rotating tool 46G to rotate. As the rotating tool 46G rotates, the rubber material 46H rotates (=wipes) while in contact with the light-transmitting opening 46C, thereby removing impurities, such as soil and rainwater, adhering to the surface of the light-transmitting opening 46C and wiping the light-transmitting opening 46C toward the sensor main body 46D as needed to keep it clean. This prevents a decrease in the measurement accuracy of the sensor main body 46D due to contamination of the light-transmitting opening 46C, and also makes it possible to more stably measure the distance L of the optical measuring device 45, thereby preventing malfunctions.

[0079] (2) When the optical measuring device measures the distance to another point on the rotating part In the above embodiment, the optical measuring device 45 is described as measuring the distance L to the flange end surface 15A of the wheel 15, but the distance measurement is not limited to this. That is, for example, as shown by the dashed line in Figure 4, the optical measuring device 45 may measure the distance L' to another location on the rotating part, in this example, the end face of the brake hub 40, instead of the distance L. In this case, the end face of the brake hub 40 corresponds to the predetermined position (deformed part) on the rotating part that is the measurement target. In this case, the same effect can be obtained by using the same method as above.

[0080] (3) When the optical measuring device is installed in a different location on the non-rotating part In the above embodiment, an example was shown in which the optical measuring device 45 was attached to the plate 44 provided on the flange portion 12D of the spindle 12, but the installation location is not limited to this. That is, for example, as shown by the two-dot chain line in FIG. 4, a plate 44 may be provided on a retainer 41E constituting a brake device 41 as a non-rotating part, and an optical measuring device 45 may be attached to the side of the plate 44 opposite to the brake hub 40. In this case, instead of the distance L in FIG. 4, the distance to the flange end surface 15A of the wheel 15 (distance L″ in the drawing) is measured by the optical measuring device 45. In this case, the same effect can be obtained by the same method as above.

[0081] (4) Other The present invention has been described above by taking as an example a case where it is applied to a rear-wheel drive dump truck 1. However, the present invention is not limited to this, and may be applied to, for example, a front-wheel drive dump truck or a four-wheel drive dump truck in which both the front and rear wheels are driven. In this case, too, the same effects as those described above can be obtained.

[0082] <Problems to be solved and effects of the embodiments> The problems to be solved by the embodiments and the effects of the embodiments are not limited to those described above. That is, the present embodiments may solve problems or achieve effects that are not described above, or may solve only some of the problems or achieve only some of the effects that are described. <About shape, numbers, structure, and time series> The components illustrated in the embodiments and drawings may be modified and improved as desired within the scope of the technical concept of the present embodiment in terms of shape, numerical value, or the structure or chronological relationship of multiple components.

[0083] <parallel> In the above explanation, "parallel" does not mean parallel in the strict sense. In other words, "parallel" means "substantially parallel," allowing for tolerances and errors in design and manufacturing.

[0084] <equal to> The term "equal" in the above description does not have a strict meaning. In other words, "equal" means "substantially equal" taking into account tolerances and errors in design and manufacturing.

[0085] In addition to the above, the methods according to the above embodiments and modifications may be used in appropriate combination.

[0086] Although not specifically illustrated, various modifications can be made to this embodiment without departing from the spirit of the present invention. [Explanation of symbols]

[0087] 1 dump truck 2. Body 4 rear wheels 4A Inner tire 4B outer tire 4L left rear wheel 4R right rear wheel 5 Cargo bed 11 Running gear 11L Left side running gear 11R Right side traveling device 12 spindles 12D Brake mounting flange 15 Wheels 15A Flange end face (specified position, deformation area) 21 Electric motor 25 Planetary gear reducer (reduction gear) 26 Planetary gear reduction mechanism 34 Planetary gear reduction mechanism 40 Brake hub 41 Brake equipment 41E Retainer 43 volts 44 Plate (dustproof material) 44A flange 44L Lower plate (split piece) 44U Upper plate (split piece) 45 Optical Measuring Equipment 45B Sensor body (optical sensor) 45C Cover (dustproof wall) 45Ca transparent port 46B Top plate (dustproof wall) 46C Translucent port 46D Sensor body (optical sensor) 46G Rotating Tool 46H rubber material 210 processors 215 Storage device (storage unit) 220 Volatile Storage Device 230 Non-volatile storage device 233 Correlation Storage 240 Display section K correction factor k axis center (rotation axis center) L Distance measured by the sensor L': Distance measured by the sensor L″ Distance measured by the sensor L0 Distance measured by the sensor - L1 Distance measured by the sensor △L distance deviation M Gap W Axle load W0 constant

Claims

1. A measuring device attached to a traveling device of a dump truck that travels with a load on a loading platform provided on the top of the vehicle body, the measuring device is an optical sensor attached to a non-rotating part of the traveling device that does not rotate when traveling, and measures the distance to a predetermined position of a rotating part using an emitted electromagnetic wave; A determination unit that determines an estimated axle load of the dump truck based on the measurement result of the optical sensor; A display unit that displays the estimated axle load determined by the determination unit; A storage unit that stores a correlation between an actual measurement value of the axle load of the dump truck measured in advance and an actual measurement value of the distance, The determination unit applies the correlation stored in the storage unit to the measurement value of the optical sensor while the vehicle is traveling, thereby determining the corresponding estimated axle load.

2. 2. The measuring device according to claim 1, The determination unit The estimated axle weight is determined using a correction coefficient set according to each of a plurality of vehicle types of the dump truck. A measuring device characterized by:

3. 2. The measuring device according to claim 1, a light-transmitting opening that allows light to exit from the optical sensor and light to enter the optical sensor; and a dust-proof wall that covers at least the measurement side of the optical sensor. A measuring device characterized by:

4. 4. The measuring device according to claim 3, The dustproof wall further includes a wiping mechanism capable of wiping the light transmitting opening. A measuring device characterized by:

5. In a traveling device of a dump truck that travels with a load loaded on a loading platform provided on the upper part of the vehicle body, a motor provided on the vehicle body; a rotating section including a tire that is rotatably supported on the vehicle body and rotates by the rotational driving force of the motor during running; an optical sensor attached to a non-rotating part of the vehicle body that does not rotate during travel, the optical sensor measuring the distance to a deformation part of the rotating part using an emitted electromagnetic wave; A determination unit that determines an estimated axle load of the dump truck based on the measurement result of the optical sensor; a display unit that displays the estimated axle load determined by the determination unit; A traveling device for a dump truck, comprising:

6. The dump truck traveling device according to claim 5, The rotating portion has a rotation axis that is substantially horizontal, The optical sensor The distance in the substantially horizontal direction from the optical sensor in the non-rotating portion to the deformed portion of the rotating portion is measured. A dump truck traveling device characterized by:

7. The dump truck traveling device according to claim 5, The rotating portion further includes: a wheel on which the tire is mounted, The non-rotating portion further comprises: a spindle inserted into the inner circumferential side of the wheel and having the motor disposed on one end thereof; a dustproof member having a substantially annular shape and provided on the outer periphery of the spindle; and The rotating portion further includes: a shaft coupled to the output shaft of the motor, inserted through the inner periphery of the spindle, and protruding from the other end of the spindle; a reducer disposed between the shaft and the wheel on the other end side of the spindle, the reducer transmitting power from the shaft to the wheel; and The optical sensor is provided on the dustproof member. A dump truck traveling device characterized by:

8. The dump truck traveling device according to claim 7, The dustproof member is The substantially annular shape is configured so as to be divisible into a plurality of pieces in the circumferential direction at a predetermined portion. A dump truck traveling device characterized by:

9. The dump truck traveling device according to claim 7, The optical sensor Measure the distance from the optical sensor to the end face of the wheel. A dump truck traveling device characterized by:

Images